Fixation and protection of an implanted medical device

ABSTRACT

Fixation and protective components for use with implantable medical devices, such as access ports and catheters, are disclosed. In one embodiment, a protective sleeve is employed about a catheter so as to distribute compressive loads and ensure patency of the catheter lumen, even in areas prone to pinch-off. A catheter assembly in one embodiment thus comprises an elongate catheter tube that defines at least one lumen. A protective mesh sleeve is disposed about an external portion of the catheter tube so as to cover at least a portion of the longitudinal length of the catheter tube. The protective sleeve is configured to distribute a compressive load on the catheter tube so as to ensure patency of the at least one lumen of the catheter tube.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.13/428,913, filed Mar. 23, 2012, now U.S. Pat. No. 9,295,809, whichclaims the benefit of U.S. Provisional Patent Application No.61/467,330, filed Mar. 24, 2011, and titled “Antimicrobial FixationDevice for an Implantable Medical Device,” each of which is incorporatedherein by reference in its entirety.

BRIEF SUMMARY

Briefly summarized, embodiments of the present invention are directed tofixation and protective components for use with implantable medicaldevices, such as access ports and catheters. In one embodiment,configurations for directly securing an implantable medical devicewithin a tissue pocket of the patient are disclosed. In anotherembodiment, indirect securement of the medical device within the pocketusing a fixation component is disclosed. In yet another embodiment, aprotective sleeve is employed about a catheter so as to ensure patencyof the catheter lumen, even in areas prone to excess catheter tubecompression and pinch-off.

For example, a catheter assembly in one embodiment comprises an elongatecatheter tube that defines at least one lumen. A protective mesh sleeveis disposed about an external portion of the catheter tube so as tocover at least a portion of the longitudinal length of the cathetertube. The protective sleeve is configured to distribute a compressiveload on the catheter tube so as to ensure patency of the at least onelumen of the catheter tube, thus enabling fluids to acceptably flowthrough the catheter tube.

These and other features of embodiments of the present invention willbecome more fully apparent from the following description and appendedclaims, or may be learned by the practice of embodiments of theinvention as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

A more particular description of the present disclosure will be renderedby reference to specific embodiments thereof that are illustrated in theappended drawings. It is appreciated that these drawings depict onlytypical embodiments of the invention and are therefore not to beconsidered limiting of its scope. Example embodiments of the inventionwill be described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1 is a simplified view showing placement of an implantable accessport and catheter into a body of a patient;

FIG. 2 shows an implantable access port secured within a tissue pocketaccording to one embodiment;

FIG. 3A is a perspective view of a mesh-based fixation component for animplantable medical device according to one embodiment;

FIG. 3B is a perspective view of the fixation component of FIG. 3Aattached to an implantable access port according to one embodiment;

FIG. 4 shows the implantable access port and fixation component of FIG.3B secured within a tissue pocket according to one embodiment;

FIGS. 5A and 5B are partially exploded and assembled views,respectively, of an insertion tool for inserting the suture screws shownin FIG. 4 according to one embodiment;

FIG. 6 is a perspective view of a fixation component attached to animplantable access port according to one embodiment;

FIG. 7 is a perspective view of a fixation component attached to animplantable access port according to one embodiment;

FIG. 8 is a perspective view of a fixation component attached to animplantable access port according to one embodiment;

FIG. 9 is a perspective view of a catheter tube including a protectivesleeve according to one embodiment; and

FIG. 10 shows the catheter tube of FIG. 9 in place within the body of apatient according to one embodiment.

DETAILED DESCRIPTION OF SELECTED EMBODIMENTS

Reference will now be made to figures wherein like structures will beprovided with like reference designations. It is understood that thedrawings are diagrammatic and schematic representations of exemplaryembodiments of the present invention, and are neither limiting nornecessarily drawn to scale.

For clarity it is to be understood that the word “proximal” refers to adirection relatively closer to a clinician using the device to bedescribed herein, while the word “distal” refers to a directionrelatively further from the clinician. For example, the end of acatheter placed within the body of a patient is considered a distal endof the catheter, while the catheter end remaining outside the body is aproximal end of the catheter. Also, the words “including,” “has,” and“having,” as used herein, including the claims, shall have the samemeaning as the word “comprising.”

Embodiments of the present invention are generally directed to fixationand protective components for use with implantable medical devices, suchas access ports and catheters. In one embodiment, configurations fordirectly securing an implantable medical device within a tissue pocketof the patient are disclosed. In another embodiment, indirect securementof the medical device within the pocket using a fixation component isdisclosed. In yet another embodiment, a protective sleeve is employedabout a catheter so as to ensure patency of the catheter lumen, even inareas prone to pinch-off.

Reference is first made to FIG. 1, which shows in simplified forminternal portions of a patient body 10, including a subclavian vein 12,which is representative of veins into which a catheter may be insertedfor the delivery of medicaments to the patient, for instance. Animplantable access port (“port”) 20 is shown after placement into thebody 10 and is operably connected to a catheter 30. Specifically, thecatheter 30 includes a catheter tube 32 defining a proximal end 32A thatoperably attaches to a stem of the port 20. A distal portion of thecatheter tube 32 is disposed within the subclavian vein 12 such that adistal end 32B of the catheter tube is disposed proximate the heart 38of the patient. Note that the catheter can be disposed in any one of avariety of vessels or other internal portions of the body 10, inaddition to what is shown here.

In greater detail, both the port 20 and the catheter 30 are disposedbeneath the patient's skin after placement by a health professional. Theport 20 is typically disposed within a subcutaneous pocket definedwithin the tissue of the patient. Note that the particular placement ofthe port shown in FIG. 1 is merely one example of possible portplacement. A tunneled portion 34 of the catheter tube 32 extends throughthe subcutaneous tissue of the patient from port pocket at the proximalcatheter tube end 32A to a vessel insertion site 36, where the cathetertube enters the vein 12. As mentioned, the distal portion of thecatheter tube 32 extends within the vein 12 toward the heart, as shown,and terminates at the distal catheter tube end 32B.

FIG. 2 shows the port 20 disposed in a tissue pocket 40 defined intissue 42 below the skin 44 of the patient, as mentioned above. Anincision 46 is also shown, used to access the pocket 40 and place theport 20 therein. As shown, the port 20 generally includes a body 22 towhich is attached a needle-penetrable septum 24 that covers a fluidreservoir. A stem 26 extends from the body and is configured to bereceived by the proximal end 32A of the catheter tube 32 so as toestablish fluid communication between the fluid reservoir and the lumenof the catheter 30.

In accordance with one embodiment, the port 20 is secured directly tothe tissue pocket 40 via use of an adhesive 50 interposed between abottom surface 22A of the port and a surface of the pocket. Thusadhesive 50 thus prevents undesired movement of the port 20 within thepocket 40. In one embodiment, therefore, the tissue pocket 40 is firstcreated by the health care professional. The adhesive 50 is then appliedto the bottom (or other suitable) surface 22A of the port 20, the pocketsurface, or to both surfaces. The port 20 is then placed into the pocket40 and pressed into place, if needed. In one embodiment, the port 20 ismanually or otherwise temporarily secured until the adhesive cures. Thestem 26 of the port 20 is attached to the proximal end 32A of thecatheter 30 if the catheter has been previously inserted into the vein12 (FIG. 1) and subcutaneously tunneled to the pocket 40. The pocket 40is then subsequently closed at the incision 46.

The adhesive 50 can include any biocompatible substance that issufficient for securing the port 20 in place. Examples of suitableadhesives include wound closure adhesives, a silicone-based MG 7-9850 ABadhesive available from Dow Corning, butyl-Z-cyanoacrylate,2-Octyl-cyanoacrylate, and DERMABOND™ adhesive available from Ethicon,Inc. Of course, other suitable substances may also be used. In anotherembodiment, the adhesive may be absorbable/resorbable, or may includebiocompatible epoxy, light-cured, heat-cured, or time-cured adhesives.

FIGS. 3A and 3B depict various details of a fixation component forsecuring a port or other medical device within a tissue pocket,according to one embodiment. In particular, the fixation component ofthe present embodiment includes a flexible mesh sheet 60 of woven orintersecting strand material design. In one embodiment, syntheticmaterials including polypropylene, para-aramid synthetic fiber soldunder the trademark KEVLAR®, polyethylene fibers sold under thetrademark TYVEK®, polyamides such as nylon, semi-synthetic materialssuch as rayon, etc.

The size and shape of the holes defined by the mesh, as well as the sizeand material type of the strands can vary, but in one embodiment themesh size is selected so as to promote tissue in-growth into the mesh.As such, the representation of the mesh sheet shown and described hereis merely one example and is not meant to be limiting. In oneembodiment, the strand diameter is about 0.005 inch or less to provideflexibility to the sheet. In one embodiment, the size of the meshopenings is about two millimeters or less. In yet another embodiment,the size of the mesh openings is about 0.1 millimeter.

In one embodiment, the material from which the mesh of the sheet 60 ismade includes an absorbable/resorbable material. Examples of resorbablematerials include L-lactide and Co DL-lactide materials, cellulose,fibrin, collagen, etc. In another embodiment, a tyrosine-basedresorbable polymer, available from TYRX, Inc., Monmouth Junction, N.J.,can be employed for the mesh. Other biocompatible materials can also beacceptably used.

As seen in FIG. 3B, the mesh sheet 60 is configured to attach to theport 20 and is configured for placement in a subcutaneous tissue pocketin order to secure the port within the pocket, as will be seen. In thepresent embodiment, a suitable and biocompatible adhesive can be used toaffix the mesh sheet 60 to the bottom surface 22A of the port 20,including those adhesive referenced above in connection with thediscussion of FIG. 2. In another embodiment other suitable modes ofaffixation can be employed including mechanical fixation (via hooks,snaps, ties, etc.), adhesion via vulcanized silicone, heat staking,ultrasonic welding, etc. In yet another embodiment, the mesh sheet canbe sewn or otherwise secured about the port.

FIG. 4 shows the manner in which the mesh sheet 60 is employed as afixation component to secure the port 20 within the pocket 40. As shown,the port 20—with the mesh sheet 60 attached to the port body bottomsurface 22A via the adhesive 50—is disposed within the tissue pocket 40.The mesh sheet 60 in turn is secured to surrounding tissue of the pocket40 via a plurality of fasteners, in this case threaded, screw-typefasteners 64. As shown, the fasteners 64 extend through the mesh sheet60 and into the pocket tissue so as to secure the mesh sheet within thepocket, which in turn secures the port 20 in place within the pocket. Asbefore, securement of the port 20 within the pocket 40 preventsundesired port movement, including flipping of the port within thepocket.

It is appreciated that the mesh sheet can be secured to tissue withinthe pocket by other modes, including adhesives (such as those discussedabove in connection with FIG. 2 and including absorbable/resorbableadhesives), wire sutures, traditional sutures, etc.

In one embodiment, the mesh structure of the sheet 60 is employed as a“scaffold” to facilitate tissue in-growth into the sheet and furthersecure the medical device to the patient's tissue. In the case that itis absorbable/resorbable, the mesh sheet 60 need not be removed when theport 20 is removed from the patient after treatment is complete. In sucha case, the fasteners 64 or other fixation component used to secure themesh sheet 60 in place can be employed as temporary fixation componentsuntil tissue in-growth occurs and can be absorbable/resorbable in oneembodiment.

It is appreciated that in other embodiments the sheet can be configuredas a substantially solid structure (woven or unwoven). It is furtherappreciated that in one embodiment the mesh sheet includes anantimicrobial substance to reduce or prevent microbial infection of theaccess port or other implantable device. In one embodiment theantimicrobial substance can include a dual component mixture ofMinocycline and Rifampin, available from TYRX, Inc. In anotherembodiment, a coating including silver and/or iodine can be employed.These and other antimicrobial treatments are therefore contemplated.

FIGS. 5A and 5B depict various details regarding a suture insertion tool70 that can be used to insert the fasteners 64 through the mesh sheet 60and into the tissue of the pocket 40 to secure the port 20 therein (FIG.4). Again, the fasteners are but one example of fixation components andit is appreciated that the particular design of the insertion tooldescribed here can vary according to the configuration of the fastenersor other fixation component. In one embodiment, for instance, thefasteners include PERMAFIX™ fasteners from Davol Inc, Warwick, R.I. Inother embodiments, the fasteners can include, barbed, rivet-like, orother suitable fastener types.

As shown in FIGS. 5A and 5B, the insertion tool 70 includes a shaft 72with a round external cross-section and a handle 74 disposed at aproximal end thereof. A pin guide 76 extends from the distal end of theshaft 72. A plurality of fasteners 64 can be housed within the hollowshaft 72 and can be guided into place within the pocket 40 by the pinguide 76. The internal cross-section of the hollow shaft 72 may besquare. The square distal end opening of the shaft 72 can be used as arotatable driver to thread the each fastener through the mesh sheet 60and into the tissue, as shown in FIG. 4. It is appreciated that theshape of the insertion tool shaft can vary according to theconfiguration of the fastener.

FIGS. 6, 7, and 8 depict possible shape and edge configurations for themesh sheet 60. As shown, a substantially solid edge portion 80 isincluded about the perimeter of each mesh sheet 80. The edge portion 80serves as a suitable location through which the threaded fasteners 64(FIG. 4) or other type of fasteners can pierce the sheet 60, thusoffering a secure engagement between the fastener and the sheet. Theedge portion 80 can also assist in providing a gripping surface forremoval of the port from the pocket. Further, the edge portion 80 canassist in preventing unintended pullout of the fasteners insertedthrough the mesh of the mesh sheet 60. Also, the edge portion 80provides a smooth perimeter surface for the mesh sheet 60, thuspreventing irritation within the pocket 40.

More generally, note that rings, ridges, bands, and other structures canbe added to the mesh sheet or other suitable fixation device to enhanceconnection of the fasteners therewith and/or to facilitateinsertion/removal of the medical device from the pocket. Thesestructures can include absorbable/resorbable materials, in oneembodiment. Also, the mesh sheet or other fixation component can bemanufactured in a variety of sizes, shapes, thicknesses, etc., toaccommodate differently-sized implantable devices. In one embodiment,the mesh sheet as a fixation component can fully envelop the medicaldevice and can include a closure device to prevent escape of the medicaldevice therefrom. Again, in one embodiment the mesh sheet can includeantimicrobial properties in addition to fixation properties.

Reference is made to FIG. 9 in describing details of a hollow,cylindrical protective sleeve 90 that is disposed over a portion of theouter surface of a catheter tube such as the catheter tube 32 of thecatheter 30 disposed in the vessel 12, shown in FIG. 1. In the presentembodiment, the sleeve 90 defines a fine mesh structure. Desiredcharacteristics of the material from which the mesh of the sleeve 90 ismade includes, according to one embodiment, high tensile strength andfine, filamentary structure to enable the formation of the fine meshconfiguration of the sleeve. Possible biocompatible materials from whichthe sleeve can be manufactured include polypropylene, and para-aramidsynthetic fiber sold under the trademark KEVLAR®, in one embodiment,though other suitable materials can also be employed, such as thosediscussed above in connection with the mesh sheet 60 of FIGS. 3A and 3B.In one embodiment, the diameter of the strand material from which themesh sleeve 90 is formed is about 0.005 inch or less to provideflexibility. In one embodiment, the size of the mesh openings is abouttwo millimeters or less. In yet another embodiment, the size of the meshopenings is about 0.1 millimeter.

In one embodiment, the sleeve mesh has a satin-type weave configuration,though other weaves may also be acceptably used. In the presentembodiment, the filamentary material from which the sleeve is madeincludes a diameter of about 0.001 inch or less, though it isappreciated that a variety of material diameters may acceptably be used.

The sleeve 90 can be placed at any point along the longitudinal lengthof the catheter tube 32, such as the position shown in FIG. 9, and isaffixed to the outer catheter tube surface via a suitable adhesive orother mode for fixation. In another embodiment, the sleeve can beinitially slidable along the length of the catheter tube for subsequentfixation once the desired sleeve position is known. In yet anotherembodiment, the sleeve remains slidable with respect to the cathetertube after final placement of the catheter.

In accordance with one embodiment, one possible position for the sleeve90 along the length of the catheter tube 32 is proximate a point wherethe catheter tube passes near or through an obstruction that may exposethe catheter tube to unintended compression, also referred to herein aspinch-off. FIG. 10 shows one possible pinch-off location. Indeed, FIG.10 shows a clavicle 100 and a first rib 102 of the patient, betweenwhich the subclavian vein 12 passes. The costaclavicular ligament 104spans between the clavicle 100 and the first rib 102 so as to bepositioned proximate the subclavian vein 12. In some cases where it isnot inserted into the subclavian vein 12 prior to the vein's passagebeneath the clavicle 100, the catheter tube 32 will be advanced by thehealth care professional such that the catheter tube pierces a hole 106in and passes through the ligament 104. When this occurs, compressiveforces are imposed on the catheter tube 32 by the ligament 104, whichmay undesirably result in pinch-off.

The sleeve 90 positioned as shown in FIG. 10 is configured to preventthis and other pinch-off scenarios by distributing the compressive loadincident on the catheter tube 32 away from the point of tube passagethrough the ligament 104 and thus cushioning the catheter tube. Thisresults in the lumen(s) defined by the catheter tube remaining patentand functional. Note that this is but one example of a pinch-offscenario where the sleeve can improve catheter tube patency; otherpositions and configurations are also contemplated. Note further thatthe sleeve 90 assists in preventing kinking of the catheter tube 32, inone embodiment, and can increase catheter longevity by reducing cathetertube fatigue.

In one embodiment, a tissue growth enhancer can be applied to orotherwise included with the sleeve so as to enhance repair and healingof tissue surrounding the subcutaneous tunnel through which the cathetertube is passed, such as the tunneled portion shown at 34 in FIG. 1. Inanother embodiment, the sleeve can be treated so as to provideantimicrobial properties. In yet another embodiment, the sleeve can beconfigured as absorbable/resorbable so as to obviate the need forremoval of the sleeve from the tunneled portion of the patient's bodywhen the catheter is no longer needed.

Embodiments of the invention may be embodied in other specific formswithout departing from the spirit of the present disclosure. Thedescribed embodiments are to be considered in all respects only asillustrative, not restrictive. The scope of the embodiments is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes that come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed is:
 1. A method for securing an implantable medicaldevice in a subcutaneous tissue pocket within a patient, the methodcomprising: defining the subcutaneous tissue pocket in the patient;applying an adhesive to at least one of a portion of the pocket and anouter surface of the medical device; and placing the medical device inthe pocket such that the medical device is secured in place within thepocket by the adhesive.
 2. The method for securing as defined in claim1, further comprising holding the medical device stationary afterplacement in the pocket for a time sufficient for the adhesive to cure.3. The method for securing as defined in claim 1, wherein the medicaldevice includes an implantable access port, and wherein the adhesiveincludes one of an absorbable/resorbable adhesive, a biocompatibleepoxy, a light-cured adhesive, a heat-cured adhesive, and a time-curedadhesive.
 4. The method for securing as defined in claim 1, whereinapplying the adhesive further includes applying the adhesive to a bottomsurface of the medical device.
 5. The method for securing as defined inclaim 1, wherein applying the adhesive further comprises applying anadhesive including at least one of a wound closure adhesive, avulcanized silicone, and a cyanoacrylate.
 6. A fixation system for animplantable medical device, comprising: the implantable medical device;and a mesh sheet affixed to the medical device, the mesh sheet affixablewithin a tissue pocket defined in a body of a patient so as to securethe implantable medical device within the pocket.
 7. The fixation systemas defined in claim 6, wherein the mesh sheet is flexible and isattached to an outer surface of the medical device via at least one ofan adhesive and a mechanical fastener.
 8. The fixation system as definedin claim 6, wherein the mesh sheet is affixed to tissue within thepocket via at least one of an adhesive and mechanical fasteners.
 9. Thefixation system as defined in claim 8, wherein the mesh sheet isattached to tissue within the pocket via insertion of threaded fastenersthrough the mesh sheet.
 10. The fixation system as defined in claim 9,wherein an insertion tool is used to threadably engage the threadedfasteners with the mesh sheet and tissue, the fasteners being initiallyreceived on a pin guide extending from a shaft of the insertion tool.11. The fixation system as defined in claim 10, wherein the shaft of theinsertion tool is hollow and defines an internal square cross-section,wherein a head portion of the fasteners is square, and wherein a distalportion of the shaft can be employed to threadably engage the fastenerwith the mesh sheet and tissue.
 12. The fixation system as defined inclaim 6, wherein the mesh sheet includes an antimicrobial substance toinhibit the presence of microbes on the mesh sheet after implantation inthe pocket.
 13. The fixation system as defined in claim 6, wherein atleast a portion of a perimeter of the mesh sheet includes asubstantially solid edge portion suitable for threadably receivingfasteners therethrough.
 14. The fixation system as defined in claim 6,wherein the mesh sheet includes an absorbable/resorbable component. 15.The fixation system as defined in claim 6, wherein strand material fromwhich the mesh sheet is formed includes a diameter of about 0.001 inch.